Abstract-Recent empirical studies have investigated the use of source code metrics to predict the change-and defect-proneness of source code files and classes. While results showed strong correlations and good predictive power of these metrics, they do not distinguish between interface, abstract or concrete classes. In particular, interfaces declare contracts that are meant to remain stable during the evolution of a software system while the implementation in concrete classes is more likely to change.This paper aims at investigating to which extent the existing source code metrics can be used for predicting change-prone Java interfaces. We empirically investigate the correlation between metrics and the number of fine-grained source code changes in interfaces of ten Java open-source systems. Then, we evaluate the metrics to calculate models for predicting change-prone Java interfaces. Our results show that the external interface cohesion metric exhibits the strongest correlation with the number of source code changes. This metric also improves the performance of prediction models to classify Java interfaces into change-prone and not change-prone.

Continuous Delivery is an agile software development practice in which developers frequently integrate changes into the main development line and produce releases of their software. An automated Continuous Integration infrastructure builds and tests these changes. Claimed advantages of CD include early discovery of (integration) errors, reduced cycle time, and better adoption of coding standards and guidelines. This paper reports on a study in which we surveyed 152 developers of a large financial organization (ING Nederland), and investigated how they adopt a Continuous Integration and delivery pipeline during their development activities. In our study, we focus on topics related to managing technical debt, as well as test automation practices. The survey results shed light on the adoption of some agile methods in practice, and sometimes confirm, while in other cases, confute common wisdom and results obtained in other studies. For example, we found that refactoring tends to be performed together with other development activities, technical debt is almost always "self-admitted", developers timely document source code, and assure the quality of their product through extensive automated testing, with a third of respondents dedicating more than 50% of their time to do testing activities.

Abstract-In the service-oriented paradigm web service interfaces are considered contracts between web service subscribers and providers. However, these interfaces are continuously evolving over time to satisfy changes in the requirements and to fix bugs. Changes in a web service interface typically affect the systems of its subscribers. Therefore, it is essential for subscribers to recognize which types of changes occur in a web service interface in order to analyze the impact on his/her systems.In this paper we propose a tool called WSDLDiff to extract fine-grained changes from subsequent versions of a web service interface defined in WSDL. In contrast to existing approaches, WSDLDiff takes into account the syntax of WSDL and extracts the WSDL elements affected by changes and the types of changes. With WSDLDiff we performed a study aimed at analyzing the evolution of web services using the fine-grained changes extracted from the subsequent versions of four real world WSDL interfaces.The results of our study show that the analysis of the finegrained changes helps web service subscribers to highlight the most frequent types of changes affecting a WSDL interface. This information can be relevant for web service subscribers who want to assess the risk associated to the usage of web services and to subscribe to the most stable ones.

This paper presents an empirical study in an industrial context on the production of software using a framework. Frameworks are semicomplete applications, usually implemented as a hierarchy of classes. The framework is developed first, then several applications are derived from it. Frameworks are a reuse technique that supports the engineering of product lines. In the study, we compare quality (in the sense of rework effort) and productivity in traditional and framework-based software production. We observe that the latter is characterized by better productivity and quality, as well as a massive increase in productivity over time, that we attribute to the effect of learning the framework. Although we cannot extrapolate the results outside the local environment, enough evidence has been accumulated to stimulate future research work.

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